The present invention generally relates to an apparatus for externally fixing a joint fracture or dislocation. In particular, the present invention provides an apparatus that fixes a joint injury, such as a joint fracture or dislocation while allowing distraction coupled with dynamic movement and flexion of the fractured/dislocated joint.
It is well known in the art to place fractures, particularly comminuted fractures, under distraction to prevent compressive forces, such as those transmitted by tendons and ligaments, from collapsing the bone from its reduced and stabilized position during healing. For example, the proximal interphalangeal (PIP) joint of a finger is commonly injured resulting in a comminuted fracture or fracture/dislocation. Often, a comminuted joint injury such as those to the PIP joint can be adequately treated by traditional means. These traditional and well-known methods include fixation or splinting, but sometimes more traumatic injuries occur to the PIP joint that can be difficult to effectively manage by these traditional methods because these traditional methods do not alleviate post-trauma complications. Specifically, a noted effect of the healing process that leads to post-trauma complications is stiffness of joints and deterioration of cartilage tissue of the fractured bone or dislocated joint.
To treat these more traumatic PIP joint injuries, fixation can be combined with distraction and early motion of the joint. Early mobilization of the joint tends to produce better long term function. By coupling fixation with early distraction and mobilization of the fractured PIP joint, potential problems such as contracture, loss of motion, and post-traumatic arthritis to the finger may be avoided.
As stated above, in the past, other treatment methods have been used to treat these PIP joint fractures. Such treatment techniques include open reduction and internal fixation, volar plate arthoplasty, splinting, external fixation and distraction. Dynamic distraction has been used as treatment for comminuted fractures of the PIP joint to limit the aforementioned complications. Dynamic distraction combines the treatment method of distraction with early movement and mobilization of the joint to create a treatment method for these difficult PIP joint fractures.
In recent years, new methods to manage these difficult injuries have been developed. Schenck, in U.S. Pat. No. 4,724,827, discloses a dynamic distraction method. The Schenck device utilizes a cast to immobilize the wrist joint and any other additional joints of the hand and fingers, as needed. An actuator is connected to the cast. The actuator forms a vertical hoop about the distal tip of the broken finger with the proximal joint at the radial center of the hoop. The finger, at its distal ends, is then connected by elastic bands to the hoop to maintain distal distraction. The bands are slidable along the hoop so as to provide passive motion in an effort to minimize cartilage deterioration during the healing process
A second device attempting to alleviate the complications associated with PIP joint fractures has been described by Hotchkiss. The Hotchkiss Compass Hinge, as the invention is known, uses a hinge with a worm gear to stabilize and distract fractures of the PIP joint. The Hotchkiss Compass Hinge is applied unilaterally to the fractured digit. The Compass Hinge has a proximal pin block and a distal pin block. First, an axis pin, usually formed from a Kirschner wire, is set through the PIP axis of rotation. Once the axis pin is in place, the device's hinge is slid over the pin, and the proximal and distal pin blocks are then affixed to the injured finger by pinning the blocks in place to the respective bones. The two portions of the device that comprise the hinge are then affixed to the blocks. A worm gear between and connecting the hinge portions limits the movement of the joint while also providing some distraction, but the device can only be applied unilaterally. Furthermore, due to the bulky and cumbersome nature of the device its application is realistically limited to border digits, specifically the index and small fingers.
Another well-known distraction device is the force couple wire type device described in 1987 by Agee. This device is hand crafted by a surgeon during an operation. The device is formed from three Kirschner wires ("K-wire") with two of the K-wires being smooth and the third wire being threaded. After reducing the fracture, the threaded K-wire is screwed into the dorsal portion of the joint so that it is vertical and perpendicular to the dorsal bone. The first smooth wire is inserted through the distal portion of the joint with the wire being parallel to the plane of the finger and parallel to the joint's axis of rotation. The second K-wire is then inserted proximally and parallel to the plane of the first K-wire. The distal K-wire is bent ninety degrees just outside the skin on both lateral sides of the finger. A notch is made above each bend in the distal wire, and an elastic band is placed to engage both notches and connect the distal wire to the threaded wire. The proximal K-wire is bent on each side and connected under the finger.
While devices applying distraction are known, these devices are often connected in a manner in which the distraction is difficult to maintain, the device itself may cause the digit to deviate, the device may be cumbersome and limited in its applicability to border digits and the devices are limited in their dynamic capabilities.
The present device provides improved reduction of the joint coupled with dynamic distraction.